Ultrahigh pressures: Optical observations and Raman measurements of hydrogen and deuterium to 1.47 Mbar

Abstract
Hydrogen and deuterium have been pressurized under static conditions to 1.47 Mbar, which is higher by a factor of 2 than previously reported static data. Measurements of the vibron indicate an initial increase and then a sharp decrease in frequency at pressures above 0.5 Mbar. At 1.14 Mbar the vibron frequency decreased to the zero-pressure value, and at 1.47 Mbar the frequency of the vibron in hydrogen is 90 cm1 below the value of the vibrational mode of the isolated molecule. This pronounced softening of the vibron suggests strengthened intermolecular interaction.